Magnetic Tunneling Junction Oxide Stack for Stable PMA and Fast Switching
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Solution Overview
Problem
Magnetic tunneling junction devices face challenges in achieving fast operating speeds and stable perpendicular magnetic anisotropy, which are crucial for improving the performance of magnetic memory devices like STT-MRAM.
Innovation Solution
The implementation of a magnetic tunneling junction device structure that includes a free layer doped with a non-magnetic metal and a second oxide layer with a metal oxide, where the oxygen affinity of the metal in the second oxide layer is greater than that of the non-magnetic metal, along with a capping metal layer to prevent oxygen interdiffusion and maintain interface stability, enhancing perpendicular magnetic anisotropy and operating speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a magnetic tunneling junction device is designed to achieve fast operating speed, then the operating speed improves, but the perpendicular magnetic anisotropy stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the oxide layers, specifically using a metal oxide in the second oxide layer with higher oxygen affinity than the non-magnetic metal dopant. This parameter change stabilizes the perpendicular magnetic anisotropy while enabling fast switching speeds by controlling the oxygen distribution and interface properties.
Solution Approach 2:
The patent employs composite material structures including multiple oxide layers (first oxide layer and second oxide layer with different metal compositions) and a free layer with non-magnetic metal doping. This composite approach allows simultaneous optimization of magnetic anisotropy stability and switching speed by combining materials with complementary properties.
2Stability of the object's composition
If the oxygen affinity of metal in second oxide layer is increased, then perpendicular magnetic anisotropy stability improves, but device complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the oxygen affinity difference specifically in the second oxide layer that directly contacts the free layer, rather than changing the entire device structure. This localized approach stabilizes perpendicular magnetic anisotropy at the critical interface while keeping the rest of the device structure simple and manufacturable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in improved operating speeds of less than 10 nsec and stable perpendicular magnetic anisotropy, ensuring high performance and reliability of magnetic memory devices.
Implementation Method 1
an oxygen affinity of a metal in the metal oxide of the second oxide layer is greater than an oxygen affinity of the non-magnetic metal of the free layer
Implementation Method 2
Spin Transfer Torque-Magnetic RAM (STT-MRAM) that is currently mass-produced may have an operating speed of about 50 to 100 nsec
Data Source
AI summary
Provided are a magnetic tunneling junction device having more stable perpendicular magnetic anisotropy (PMA) and/or increased operating speed, and/or a memory device including the magnetic tunneling junction device. The magnetic tunneling junction device includes a free layer having a first surface and a second surface opposite the first surface; a pinned layer facing the first surface of the free layer; a first oxide layer between the pinned layer and the free layer; and a second oxide layer on the second surface of the free layer. The free layer includes a magnetic material X doped with a non-magnetic metal/ The second oxide layer includes ZOx which is an oxide of a metal Z. An oxygen affinity of the metal Z is greater than an oxygen affinity of the non-magnetic metal X.